JP3908952B2 - Valve operating device for SOHC type internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a valve operating apparatus for an internal combustion engine, and more particularly, to a cylinder head, a single camshaft common to an intake valve and an exhaust valve, and intake air for converting the rotational motion of the camshaft into opening / closing motion of the intake valve. The present invention relates to a valve operating apparatus for an SOHC type internal combustion engine provided with valve driving means and exhaust valve driving means for converting the rotational motion of a camshaft into opening / closing motion of an exhaust valve.
[0002]
[Prior art]
  2. Description of the Related Art Conventionally, a valve operating apparatus in which a camshaft is provided with a pause portion that pauses an intake valve as an engine valve is already known, for example, from Japanese Patent Laid-Open No. 4-17707.
[0003]
[Problems to be solved by the invention]
  By the way, in the SOHC type valve operating apparatus having a single camshaft common to the intake valve and the exhaust valve, it is necessary to not only close the intake valve but also stop the exhaust valve when the cylinder is deactivated, In this case, the intake valve and the exhaust valve can be simply provided separately on the camshaft, but this makes it difficult to shorten the camshaft in the axial direction and increases the number of processing steps. become.
[0004]
  The present invention has been made in view of such circumstances, and in an SOHC type valve operating apparatus in which a camshaft is provided with a pause portion for closing and pausing an engine valve, the camshaft is shortened in the axial direction and the number of processing steps is reduced. It aims to make it possible.
[0005]
[Means for Solving the Problems]
  To achieve the above object, the present invention provides a cylinder head having a single camshaft that is common to the intake valve and the exhaust valve, and an intake valve that converts the rotational movement of the camshaft into the opening and closing movement of the intake valve. A valve operating device for an SOHC type internal combustion engine provided with a driving means and an exhaust valve driving means for converting the rotational movement of the camshaft into an opening / closing movement of the exhaust valve, wherein the intake valve driving means is linked to and connected to the intake valve. An intake valve side drive rocker arm to beAdjacent to the intake valve side drive rocker armAn exhaust valve drive means comprising: an intake valve side free rocker arm abutting on an intake valve operating cam of the camshaft; and a connection switching means capable of switching connection and release between the intake valve side drive rocker arm and the intake valve side free rocker arm. Is connected to and connected to the exhaust valve, the exhaust valve side drive rocker arm, the exhaust valve side free rocker arm that abuts the exhaust valve operating cam of the camshaft, the connection between the exhaust valve side drive rocker arm and the exhaust valve side free rocker arm, and Including a connection switching means capable of switching connection release,Intake valve sideTo drive rocker armThe first abutting portion extending toward the camshaft side is provided so as to be biased toward the intake valve side free rocker arm side in the direction along the axis of the camshaft.Provided on the abutment and exhaust valve side drive rocker arm and extending to the camshaft sideSecondThe abutting portions are arranged at the same position in the direction along the axis of the camshaft, and both the abutting portionsThe, To stop the intake and exhaust valves closedOn the camshaftAbuts against a common circular restThe common resting portion is located on one side of the intake valve side operation cam where the roller pivotally supported by the intake valve side free rocker arm is in contact with the intake valve side drive rocker arm.It is characterized by that.
[0006]
  According to such a configuration,Bias toward the free rocker arm side of the intake valve sideProvided on the intake valve side drive rocker arm and extends to the camshaft sideFirstProvided on the abutment and exhaust valve side drive rocker arm and extending to the camshaft sideSecondThe abutting portion is arranged at the same position in the direction along the axis of the camshaft, and abuts against a common resting portion of the camshaft, thereby minimizing the number of resting portions on the camshaft. be able to.The common resting portion is located on one side of the intake valve side operation cam, which is in contact with the roller supported by the intake valve side free rocker arm, near the intake valve side drive rocker arm.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.
[0008]
  1 to 5 show an embodiment of the present invention. FIG. 1 is a longitudinal side view of an internal combustion engine, FIG. 2 is a view taken along line 2-2 in FIG. 1, and FIG. 4 is a sectional view taken along line 4-4, FIG. 4 is a sectional view taken along line 4-4 in FIG. 2, and FIG. 5 is a sectional view taken along line 5-5 in FIG.
[0009]
  In FIG. 1, a cylinder block 10 of the SOHC type internal combustion engine is provided with a plurality of cylinders 11 in parallel, and pistons 12 are slidably fitted to the cylinders 11. Further, a cylinder head 14 is formed on the upper surface of the cylinder block 10 to form a combustion chamber 13 with the pistons 12. The cylinder head 14 is open to a ceiling surface of the combustion chamber 13. A pair of intake valve ports 15 and a pair of exhaust valve ports 16 are provided for each cylinder 11, and both the intake valve ports 15 communicate with an intake port 17 that opens on one side of the cylinder head 14. The exhaust valve ports 16 are communicated with exhaust ports 18 opened on the other side of the cylinder head 14. Thus, the intake manifold 19 connected to the cylinder head 14 through the intake ports 17 is provided with fuel injection valves 20 for injecting fuel toward the intake ports 17. Further, an exhaust manifold 21 communicating with the exhaust ports 18 is connected to the cylinder head 14.
[0010]
  An intake valve V as a pair of engine valves capable of individually opening and closing both intake valve ports 15 at a portion corresponding to the cylinder 11 that enables cylinder deactivation._I, V_IAre slidably fitted in guide cylinders 22 provided respectively in the cylinder head 14, and the intake valves V projecting upward from the respective guide cylinders 22 ..._I, V_IBetween the retainers 23, 23 provided at the upper end of the cylinder and the cylinder head 14._I, V_IThe valve springs 24 which surround the valve are contracted, and the intake valves V are provided by the valve springs 24._I, V_IIs biased in the direction of closing the intake valve ports 15. Further, the exhaust valves V as a pair of engine valves capable of individually opening and closing both exhaust valve ports 16._E, V_EAre slidably fitted into guide cylinders 25 provided on the cylinder head 14 respectively, and the exhaust valves V projecting upward from the respective guide cylinders 25._E, V_EBetween the retainers 26, 26 provided at the upper end of the cylinder head 14 and the cylinder head 14._E, V_EThe valve springs 27 are surrounded by the exhaust valve V._E, V_EIs urged in a direction to close the exhaust valve ports 16.
[0011]
  Referring to FIGS. 2 and 3 together, both the intake valves V_I, V_IBetween the camshaft 28 and a camshaft 28 that is linked to and connected to a crankshaft (not shown) with a reduction ratio of 1/2._I, V_IIntake valve driving means 29 for converting the opening / closing movement of the intake valve_IAnd both exhaust valves V_E, V_EBetween the camshaft 28 and the camshaft 28._E, V_EExhaust valve driving means 29 for converting into opening / closing movement of_EIs provided.
[0012]
  The camshaft 28 is rotatably supported by the cylinder head 14 and the holder 30 coupled to the cylinder head 14 so as to have an axis parallel to the rotation axis of the crankshaft. The camshaft 28 has a pair of cam journal portions 31 that are rotatably supported between the cylinder head 14 and the holder 30.₁, 31₂Are provided at intervals in the axial direction, and one cam journal portion 31 is provided.₁From the other cam journal part 31₂The camshaft 28 is provided with a substantially resting cam 32 and a resting portion 33 at positions spaced in order toward the heading.₁An exhaust valve operating cam 34, an intake valve operating cam 35, and a resting portion 33.₂Are integrally provided.
[0013]
  The intake valve operating cam 35 is provided with an intake valve V_IHas a profile that can open the valve, and has an arc-shaped base circle portion 35a centering on the axis of the camshaft 28 and a high-order portion 35b projecting radially outward from the base circle portion 35a. . Further, the substantial rest cam 32 is provided with the intake valve V._IIs substantially inactive, but the intake valve V_IAnd a base circle portion 32a having an arc shape centering on the axis of the camshaft 28, and a high-order portion 32b slightly projecting radially outward from the base circle portion 32a. And have. Furthermore, the pause unit 33₁, 33₂Is formed in a perfect circle centered on the axis of the camshaft 28, and has one resting portion 33.₁Is provided on the camshaft 28 between the substantially idle cam 32 and the exhaust valve working cam 34.₁, 31₂The rest part 33 adjacent to one of the₂The cam journal part 31₂And the cam journal portion 31 having the same outer periphery.₂Are provided on the camshaft 28 so as to be integrated with each other.
[0014]
  The exhaust valve operating cam 34 is provided with an exhaust valve V_EHas an arc-shaped base circle part 34a centering on the axis of the camshaft 28, and a high-order part 34b projecting radially outward from the base circle part 34a.
[0015]
  4 and 5 together, the intake valve driving means 29_IAre first and second intake valve side drive rocker arms 36 and 37;These first and second intake valve side drive rocker arms 36 and 37 are arranged adjacent to each other.First and second intake valve side free rocker arms 38 and 39 are provided, and these rocker arms 36 to 39 are rocked by an intake valve side rocker arm shaft 40 fixedly supported by the holder 30 at a position obliquely above the camshaft 28. It is supported freely.
[0016]
  One end of the first and second intake valve side drive rocker arms 36 and 37 has an intake valve V_I, V_IThe tappet screws 41 and 41 that are in contact with the upper ends of the two are screwed together so that their forward and backward positions can be adjusted, and the other end portions of both intake valve side drive rocker arms 36 and 37 respectively extend toward the camshaft 28 side and stop. Part 33₁, 33₂Abut eachFirstThe contact portions 36a and 37a are at the same position in the direction along the axis of the camshaft 28.(Ie, biased toward the adjacent first and second intake valve side free rocker arms 38 and 39)Provided. The second intake valve side free rocker arm 39 is disposed between both intake valve side drive rocker arms 36 and 37, and the first intake valve side free rocker arm 38 is free from the second intake valve side drive rocker arm 36 with respect to the second intake valve side drive rocker arm 36. It is arranged on the opposite side to the rocker arm 39. Thus, the first intake valve side free rocker arm 38 is pivotally supported by a roller 42 that is in rolling contact with the resting cam 32, and the second intake valve side free rocker arm 39 is in contact with the roller 43 that is in rolling contact with the intake valve side operation cam 35. Is supported.
[0017]
  Exhaust valve driving means 29_EIncludes first and second exhaust valve side drive rocker arms 44 and 45 and an exhaust valve side free rocker arm 46, and these rocker arms 44 to 46 are fixedly supported on the holder 30 at an obliquely upper position of the camshaft 28. The exhaust valve side rocker arm shaft 47 is pivotally supported.
[0018]
  The first and second exhaust valve side drive rocker arms 44 and 45 are configured to at least partially overlap the projections on the plane including the axis of the camshaft 28 with the first and second intake valve side drive rocker arms 36 and 37. The exhaust valve V is connected to one end of the exhaust valve side drive rocker arms 44, 45._E, V_EThe tappet screws 48 and 48 that are in contact with the upper end of the screw are screwed together so that their forward and backward positions can be adjusted. In addition, intake valve driving means 29 is provided at the other end of both exhaust valve side drive rocker arms 44 and 45._IThe resting portion 33 of the camshaft 28 in common with both drive rocker arms 36 and 37₁, 33₂AbutSecondAbutting portions 44a and 45a are provided. The exhaust valve side free rocker arm 46 is disposed between the exhaust valve side drive rocker arms 44 and 45, and a roller 49 that is in rolling contact with the exhaust valve side operation cam 34 is pivotally supported on the exhaust valve side free rocker arm 46.
[0019]
  A support plate 50 is fixed on the holder 30 above the intake valve side rocker arms 36 to 39 and the exhaust valve side rocker arms 44 to 46, and the intake plate driving means 29 is attached to the support plate 50._IFirst and second intake valve side free rocker arms 38 and 39, and exhaust valve driving means 29_ECorresponding to the exhaust valve side free rocker arms 46 are respectively provided with lost motion mechanisms 51. These lost motion mechanisms 51... Incorporate springs (not shown), and the corresponding lost motion mechanisms 51... Are disposed above the first and second intake valve side free rocker arms 38 and 39 and the exhaust valve side free rocker arm 46. Abutting protrusions 38a, 39a, 46a are provided to abut against. Thus, the first and second intake valve side free rocker arms 38 and 39 are elastically moved in the direction in which the first and second intake valve side free rocker arms 38 and 39 are brought into contact with the substantially idle cam 33 and the intake valve side operation cam 35 by the spring force exerted by each of the lost motion mechanisms 51. The exhaust valve side free rocker arm 46 is elastically biased in a direction to contact the exhaust valve side operation cam 34.
[0020]
  Intake valve driving means 29_IIn the first intake valve side drive rocker arm 36 and the first intake valve side free rocker arm 38, the first connection switching means 53 capable of switching the connection and disconnection of these 36, 38.₁And the second intake valve side drive rocker arm 37 and the second intake valve side free rocker arm 39 are provided with a second connection switching means 53 capable of switching the connection and disconnection of these 37, 39.₂The first intake valve side drive rocker arm 36, the second intake valve side drive rocker arm 37, and the second intake valve side free rocker arm 39 are provided with a third connection that can switch the connection and release of these 36, 37, 39. Switching means 54 is provided. Also, the exhaust valve driving means 29_EIn the first exhaust valve side drive rocker arm 44 and the exhaust valve side free rocker arm 46, the connection switching means 55 that can switch the connection and release of the connection between them.₁The second exhaust valve side drive rocker arm 45 and the exhaust valve side free rocker arm 46 are provided with connection switching means 55 that can switch the connection and release of the connection between these 45 and 46.₂Is provided.
[0021]
  Paying attention to FIG. 4, first connection switching means 53 provided between the first intake valve side drive rocker arm 36 and the first intake valve side free rocker arm 38.₁Is a piston 56 that is slidably fitted to the first intake valve side free rocker arm 38, a pressure pin 57 that is slidably fitted to the piston 56, and a space between the piston 56 and the pressure pin 57. The spring 58, the switching pin 59 that contacts the pressing pin 57, and the regulation that is slidably fitted to the first intake valve side drive rocker arm 36 by contacting the switching pin 59 on the opposite side of the pressing pin 57. A member 60 and a return spring 61 contracted between the regulating member 60 and the first intake valve side drive rocker arm 36 are provided, and the set load of the return spring 61 is set larger than the set load of the spring 58. .
[0022]
  The piston 56 is formed in a bottomed cylindrical shape having one end as a closed end, and a hydraulic chamber 62 is formed between the closed end of the piston 56 and the first intake valve side free rocker arm 38. The first intake valve side free rocker arm 38 is provided with a communication path 63 that communicates with the hydraulic chamber 62, and this communication path 63 is always in communication with an oil path 64 provided in the intake valve side rocker arm shaft 40. The
[0023]
  The pressing pin 57 has an outer diameter that can be fitted in the piston 56 and is formed in a bottomed cylindrical shape, and slides into the piston 56 with its open end facing the closed end of the piston 56. Fits freely. Thus, the spring 58 is contracted between the closed end of the piston 56 and the closed end of the pressing pin 57.
[0024]
  As shown in FIG. 4, the switching pin 59 has a contact surface between the first intake valve side free rocker arm 38 and the first intake valve side drive rocker arm 36 and the pressing pin 57. The first intake valve side drive rocker arm 36 and the first intake valve side free rocker arm 38 are slidable between the first intake valve side drive rocker arm 36 and a position fitted to the first intake valve side drive rocker arm 36.
[0025]
  The restricting member 60 is formed in a bottomed cylindrical shape with one end contacting the switching pin 59 as a closed end, and the other end of the restricting member 60 is connected to the first intake valve side drive rocker arm 36. A flange portion 60a that is slidably fitted is provided to project outward in the radial direction. The first intake valve side drive rocker arm 36 is fitted with a retaining ring 65 that contacts the flange 60a of the regulating member 60 and regulates the movement of the regulating member 60 toward one end side, that is, the switching pin 59 side.
[0026]
  The axial lengths of the switching pin 59 and the regulating member 60 are such that when the regulating member 60 moves to a position where movement of the regulating member 60 is regulated by the retaining ring 65 as shown in FIG. Is connected across the first intake valve side drive rocker arm 36 and the first intake valve side free rocker arm 38, and the two rocker arms 36, 38 are connected, but the regulating member 60 compresses the return spring 61 to compress the first intake valve side. When moving to a position where the drive rocker arm 36 comes into contact, the contact surface of the switching pin 59 with the pressing pin 57 is set so as to be at a position corresponding to between the rocker arms 36 and 38. On the other hand, as shown in FIG. 4, the piston 56 and the pressing pin 57 are mutually connected by the spring force of the spring 58 in a state where a part of the switching pin 59 is fitted to the first intake valve side free rocker arm 38. The first intake valve side free rocker arm 38 is slidably fitted so as to be separated.
[0027]
  By the way, an annular engagement groove 66 is provided on the outer periphery of the piston 56, and when the piston 56 and the pressing pin 57 are separated from each other as shown in FIG. Thus, an annular engagement groove 67 is formed around the pressing pin 57.
[0028]
  Such first connection switching means 53₁Includes a trigger mechanism 70 for regulating the operation timing.₁Is attached. The trigger mechanism 70₁Is a position where the movement of the piston 56 is restricted by engaging with the engagement groove 66 of the piston 56 or the engagement groove 67 between the piston 56 and the switching pin 59, and the engagement state with the engagement groove 66 or 67. And a trigger plate 71 capable of relative rocking with the two rocker arms 36 and 38 around the axis of the intake valve side rocker arm shaft 40 between positions where the movement of the piston 57 is allowed.
[0029]
  The first intake valve side free rocker arm 38 is provided with a slit 72, which corresponds to the engagement groove 67 in a state in which the piston 56 is displaced to the maximum extent toward the hydraulic chamber 62 as shown in FIG. Thus, the engagement groove 66 is provided in the first intake valve side free rocker arm 38, and the piston 56 and the pressing pin 57 that are in contact with each other are moved to the maximum so that the volume of the hydraulic chamber 62 is maximized. In this state, it is provided on the outer periphery of the piston 56 so as to be in a position corresponding to the slit 72.
[0030]
  The trigger plate 71 is rotatably supported on the intake valve side rocker arm shaft 40. The trigger plate 71 is integrally provided with an engagement plate portion 71 a that is detachably engaged with the engagement groove 66 or 67 from the slit 72.
[0031]
  A stopper pin 73 is fixed to the cylinder head 14 toward the first intake valve side free rocker arm 38, and a stopper 71 b that can come into contact with the stopper pin 73 from below is projected from the trigger plate 71. One end of a torsion spring 74 surrounding the intake valve side rocker arm shaft 40 is engaged with the stopper pin 73, and the other end of the torsion spring 74 is engaged with the trigger plate 71 from above. Thus, the trigger plate 71 is urged by the torsion spring 74 in the direction in which the stopper 71b is brought into contact with the stopper pin 73. With the stopper 71b in contact with the stopper pin 73, the first intake valve side free rocker arm is urged. When 38 is in a stationary state in contact with the base circle portion 32a of the rest cam 32, the engagement plate portion 71a of the trigger plate 71 can be engaged with the engagement groove 66 or 67 from the slit 72, and the first intake valve side When the free rocker arm 38 is swung in the valve opening direction by the high position portion 32 b of the substantial rest cam 32, the position of the stopper pin 73 is set so that the engagement plate portion 71 a is detached from the slit 72.
[0032]
  Such first connection switching means 53₁And trigger mechanism 70₁According to this, in a state where the hydraulic pressure in the hydraulic chamber 62 is released, the switching pin 59 is driven by the spring force of the return spring 61 so that the first intake valve side drive rocker arm 36 and the first intake valve side free rocker arm are shown in FIG. 38, the two rocker arms 36 and 38 are connected to each other.₁When the first intake valve side free rocker arm 38 is pushed down by the high position portion 32b of the substantially resting cam 32, the engagement plate portion 71a of the trigger plate 71 is disengaged from the engagement groove 67, and the first intake valve side free rocker arm is released. When 38 is in a stationary state slidably in contact with the base circle portion 32 a of the rest cam 32, it engages with the engagement groove 67.
[0033]
  Next, when hydraulic pressure is applied to the hydraulic chamber 62, the piston 56 moves until the spring 58 is compressed and abuts against the switching pin 59 when the engaging plate portion 71a is released from the engaging groove 67. 59 is in a state where both the rocker arms 36 and 38 are connected between the first intake valve side drive rocker arm 36 and the first intake valve side free rocker arm 38, and a shearing direction force acts on the switching pin 59. Therefore, the piston 56 is prevented from moving until the switching pin 59 is pushed into the first intake valve side drive rocker arm 36. However, when the first intake valve side free rocker arm 38 starts to slide in contact with the base circle portion 32a of the resting cam 32 and the force in the shearing direction on the switching pin 59 becomes small, the piston 56 causes the switching pin 59 to move to the first. It operates until it is pushed into the intake valve side drive rocker arm 36, whereby the connection state of both the rocker arms 36 and 38 is released.
[0034]
  Thus, in the state where both the rocker arms 36 and 38 are released, the trigger mechanism 70 is released.₁When the first intake valve side free rocker arm 38 is pushed down by the high position portion 32b of the substantially resting cam 32, the engagement plate portion 71a of the trigger plate 71 is separated from the engagement groove 66, and the first intake valve side free rocker arm is released. When 38 is in a stationary state where it is in sliding contact with the base circle portion 32 a of the substantially resting cam 32, it engages with the engaging groove 66. Thus, when the hydraulic pressure in the hydraulic chamber 62 is released and both the rocker arms 36 and 38 are connected, the first intake valve-side free rocker arm 38 is pushed down by the high position portion 32b of the substantially resting cam 32 and the engagement groove. 66, the piston 56 moves to a position where the volume of the hydraulic chamber 62 is minimized by the spring force of the spring 58, and then the first intake valve side free rocker arm 38 is substantially stopped cam. When the axial lines of the pressing pin 57 and the switching pin 59 coincide with each other by starting to slidably contact the base circle portion 32a of the 32, the switching pin 59 moves to a position straddling both the rocker arms 36, 38 by the spring force of the return spring 61, Both rocker arms 36 and 38 are connected.
[0035]
  Second connection switching means 53 provided between the second intake valve side drive rocker arm 37 and the second intake valve side free rocker arm 39.₂Is the first connection switching means 53 described above.₁And the second connection switching means 53.₂The connection switching means 53 to regulate the operation timing of₂Trigger mechanism 70 attached to₂Is also the trigger mechanism 70 described above.₁And the second connection switching means 53.₂And trigger mechanism 70₂A detailed description of the configuration will be omitted. Thus, the second connection switching means 53₂The first connection switching means 53₁When the connection between the first intake valve side drive rocker arm 36 and the first intake valve side free rocker arm 38 is released, the connection between the second intake valve side drive rocker arm 37 and the second intake valve side free rocker arm 39 is released. First connection switching means 53₁When the first intake valve side drive rocker arm 36 and the first intake valve side free rocker arm 38 are connected, the second intake valve side drive rocker arm 37 and the second intake valve side free rocker arm 39 are connected. The first connection switching means 53₁Switching operation is synchronized with
[0036]
  Referring to FIG. 5, the third connection switching means 54 provided in the first intake valve side drive rocker arm 36, the second intake valve side drive rocker arm 37, and the second intake valve side free rocker arm 39 is driven by the first intake valve side drive. The switching piston 76 capable of switching the connection and disconnection of the rocker arm 36 and the second intake valve side free rocker arm 39 and the connection and disconnection of the second intake valve side free rocker arm 39 and the second intake valve side drive rocker arm 37 can be switched. A switching pin 77, a regulating member 78 that is in sliding contact with the switching pin 77 on the opposite side of the switching piston 76, and a return spring 79 that biases the regulating member 78 toward the switching pin 77.
[0037]
  The switching piston 76 is slidably fitted to the first intake valve side drive rocker arm 36 so that the switching piston 76 can be fitted to the second intake valve side free rocker arm 39. A hydraulic chamber 80 is formed between the intake valve side drive rocker arm 36. The first intake valve side drive rocker arm 36 is provided with a communication passage 81 communicating with the hydraulic chamber 80, and an oil passage 82 that always communicates with the communication passage 81 is provided in the intake valve side rocker arm shaft 40. 2 connection switching means 53₁, 53₂It is provided independently of the oil passage 64 for use. Accordingly, the third connection switching means 54 is connected to the first and second connection switching means 53.₁, 53₂The switching operation can be performed independently of.
[0038]
  The switching pin 77 is slidably fitted to the second intake valve side free rocker arm 39 so that the switching pin 77 can be fitted to the second intake valve side drive rocker arm 37, and one end of the switching pin 77 contacts the other end of the switching piston 76. Be touched.
[0039]
  The restricting member 78 is formed in a bottomed cylindrical shape and is slidably fitted to the second intake valve side drive rocker arm 37, and the closed end of the restricting member 78 contacts the other end of the switching pin 77. Be touched. The second intake valve side drive rocker arm 37 is fitted with a retaining ring 83 that abuts against a flange 78a provided on the opening end side of the restricting member 78 to prevent the restricting member 78 from moving. The return spring 79 is contracted between the regulating member 78 and the second intake valve side drive rocker arm 37.
[0040]
  In the third connection switching means 54, when no hydraulic pressure is applied to the hydraulic chamber 80, the contact surfaces of the switching piston 76 and the switching pin 77 are in contact with the first intake valve side drive rocker arm 36 and the second as shown in FIG. Between the intake valve side free rocker arm 39 and the contact surface of the switching pin 77 and the restricting member 78 is between the second intake valve side free rocker arm 39 and the second intake valve side drive rocker arm 37, and therefore the rocker arms 36, 37,. 39 is in a disconnected state. Thus, when hydraulic pressure is applied to the hydraulic chamber 80, the switching piston 76 moves to the position where the other end side is fitted to the second intake valve side free rocker arm 39, and the switching pin 77 moves to the second intake side. It moves to the position where it fits in the valve side drive rocker arm 37, and the rocker arms 36, 37, 39 are connected.
[0041]
  Exhaust valve driving means 29_EThe connection switching means 55 provided in the first exhaust valve side drive rocker arm 44 and the exhaust valve side free rocker arm 46, and the second exhaust valve side drive rocker arm 45 and exhaust valve side free rocker arm 46, respectively.₁55₂The intake valve driving means 29_IFirst and second connection switching means 53 in FIG.₁, 53₂And the connection switching means 55.₁55₂The detailed description of is omitted. However, both connection switching means 55₁55₂Is configured to synchronize and switch between a connection state when the oil passage 84 provided in the exhaust valve side rocker arm shaft 47 is released and a connection release state when the oil passage 84 is operated with hydraulic pressure. , The trigger mechanism 70 described above.₁, 70₂Trigger mechanism 85 having basically the same configuration as₁, 85₂Are each connection switching means 55.₁55₂It is attached to.
[0042]
  Next, the operation of this embodiment will be described. During the engine operation, the intake valve drive means 29_IFirst, second and third connection switching means 53₁, 53₂, 54 and exhaust valve driving means 29_EConnection switching means 55₁55₂Are all in the disconnected state, the first and second intake valve side drive rocker arms 36 and 37 and the first and second exhaust valve side drive rocker arms 44 and 45 are in the rest portion 33.₁, 33₂Are in a rest state, and both intake valves V_I, V_IAnd both exhaust valves V_E, V_EAre all in a closed valve stop state, and a cylinder stop state is obtained.
[0043]
  Next, the intake valve driving means 29_I1st and 2nd connection switching means 53 with the 3rd connection switching means 54 in the connection cancellation | release state in FIG.₁, 53₂The exhaust valve driving means 29 is connected and operated._EIn both connection switching means 55₁55₁, The first intake valve side drive rocker arm 36 is connected to the first intake valve side free rocker arm 38, the second intake valve side drive rocker arm 37 is connected to the second intake valve side free rocker arm 39, and The second exhaust side drive rocker arms 44 and 45 are connected to the exhaust side free rocker arm 46. For this reason, when the first intake side free rocker arm 38 is in a substantially resting state by the substantially resting cam 32, one of the intake valves V_IIs closed and closed, while the second intake valve side free rocker arm 39 is driven by the intake valve side operation cam 35, whereby the other intake valve V is driven._IIs opened and closed with the characteristics corresponding to the profile of the intake valve side operation cam 35, and both exhaust valves V_E, V_EBoth are driven to open and close with characteristics according to the profile of the exhaust side working cam 34. Therefore, one intake valve V_IIs in a substantially resting state while the other intake valve V_IThe swirl can be generated in the combustion chamber 13 in response to the opening / closing operation of the engine so that the combustibility can be improved, and a large amount of exhaust gas circulation and lean combustion can be executed at a low speed region of the engine, thereby reducing fuel consumption. As a result, drivability can be improved.
[0044]
  Further, the intake valve driving means 29_IThe third connection switching means 54 is connected to the exhaust valve driving means 29 in FIG._EBoth connection switching means 55₁55₁Are connected to each other, the first and second intake valve side drive rocker arms 36 and 37 are connected to the second intake valve side free rocker arm 39, and the first and second exhaust side drive rocker arms 44 and 45 are connected to the exhaust side free rocker arm. 46 remains connected. For this reason, when the second intake valve side free rocker arm 39 is driven by the intake valve side operation cam 35, both intake valves V_I, V_IAre both opened and closed with characteristics corresponding to the profile of the intake valve side operation cam 35, and both exhaust valves V_E, V_EBoth of them are driven to open and close with characteristics according to the profile of the exhaust side working cam 34.
[0045]
  In such a valve operating apparatus, a pair of rest portions 33 provided on the camshaft 28.₁, 33₂One of 33₂The cam journal part 31₂The cam journal portion 31 is provided integrally with the outer peripheral surface thereof being flush with each other.₂At a position spaced axially from the rest portion 33₂Compared with the conventional one in which the camshaft 28 is provided, the camshaft 28 can be shortened in the axial direction, and the rest portion 33 is further provided.₂And cam journal 31₂Can be formed at the same time, the resting portion 33₂And cam journal 31₂As compared with the conventional one in which each is formed, the number of processing steps can be reduced.
[0046]
  Moreover, the intake valve driving means 29_IFirst intake valve side drive rocker arm 36 and exhaust valve drive means 29_EThe first exhaust valve side drive rocker arm 44 is connected to one resting portion 33.₁The intake valve drive means 29_IThe second intake valve side drive rocker arm 37 and the second exhaust valve side drive rocker arm 45 of the exhaust valve drive means are the other rest portion 33.₂The two rest portions 33 which are the minimum necessary as compared with the case where the rest portions are individually provided corresponding to the respective drive rocker arms 36, 37, 44, 45.₁, 33₂Can be provided on the camshaft 28, the axial direction of the camshaft 28 can be further shortened, and the processing man-hours can be reduced by reducing the number of rest portions formed.
[0047]
  Since the camshaft 28 can be shortened in the axial direction in this manner, the valve operating device can be made compact. In addition, the width of the cams 32 and the operating cams 34 and 35 is increased by shortening the axial direction, and the contact area between the cams 32, 34 and 35 and the rollers 42, 43 and 49 is increased. It is also possible to improve the performance.
[0048]
  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. Is possible.
[0049]
  For example, it is possible to apply the present invention to a valve operating apparatus in which only one of a pair of intake valves and one of a pair of exhaust valves are closed and stopped by a perfect stop portion. Further, the number of rocker arms is not limited to that of the above embodiment.
[0050]
【The invention's effect】
  As described above, according to the present invention, the intake valve drive means is linked to and connected to the intake valve, the intake valve side drive rocker arm,Adjacent to the intake valve side drive rocker armAn exhaust valve drive means comprising: an intake valve side free rocker arm abutting on an intake valve operating cam of the camshaft; and a connection switching means capable of switching connection and release between the intake valve side drive rocker arm and the intake valve side free rocker arm. Is connected to and connected to the exhaust valve, the exhaust valve side drive rocker arm, the exhaust valve side free rocker arm that abuts the exhaust valve operating cam of the camshaft, and the connection between the exhaust valve side drive rocker arm and the exhaust valve side free rocker arm and In a valve operating apparatus for an SOHC type internal combustion engine, including connection switching means capable of switching connection release,Intake valve sideTo drive rocker armThe first abutting portion extending toward the camshaft side is provided so as to be biased toward the intake valve side free rocker arm side in the direction along the axis of the camshaft.Provided on the abutment and exhaust valve side drive rocker arm and extending to the camshaft sideSecondThe abutting portions are arranged at the same position in the direction along the axis of the camshaft, and both the abutting portionsThe, To stop the intake and exhaust valves closedOn the camshaftAbuts against a common circular restThe common resting portion is located on one side of the intake valve side operation cam where the roller pivotally supported by the intake valve side free rocker arm is in contact with the intake valve side drive rocker arm.Therefore, the number of rest portions in the camshaft can be minimized, and the camshaft can be shortened in the axial direction, so that the valve operating device can be made compact and the number of processing steps can be reduced.
[Brief description of the drawings]
FIG. 1 is a longitudinal side view of an internal combustion engine.
FIG. 2 is a view taken along line 2-2 of FIG.
3 is a cross-sectional view taken along line 3-3 in FIG.
4 is a cross-sectional view taken along line 4-4 of FIG.
5 is a cross-sectional view taken along line 5-5 of FIG.
[Explanation of symbols]
14 ... Cylinder head
28 ... Camshaft
29_E..Exhaust valve drive means
29_I..Intake valve drive means
33₂..Suspension part
34 ... Actuating cam for exhaust valve
35 ... Intake valve operation cam
37 ... Intake valve side drive rocker arm
37a ...FirstContact part
45 ... Exhaust valve side drive rocker arm
45a ...SecondContact part
53₂..Second connection switching means (connection switching means)
55₂..Connection switching means
V_E... Exhaust valves
V_I... Intake valves

Claims (1)

The cylinder head (14) has a single camshaft (28) common to the intake valve (V _I ) and the exhaust valve (V _E ), and the rotational movement of the camshaft (28) is controlled by the intake valve (V _I). ) and the intake valve driving means for converting the closing movement of (29 _I), the rotational movement of the exhaust valve and (exhaust valve driving means for converting the closing movement of the V _E) (29 _E) is provided in the camshaft (28) A valve operating device for an SOHC type internal combustion engine,
The intake valve drive means (29 _I ) is disposed adjacent to the intake valve side drive rocker arm (37) linked to and connected to the intake valve (V _I ), and the intake valve side drive rocker arm (37), so that the camshaft (28 The intake valve side free rocker arm (39) abutting on the intake valve actuation cam (35), and the connection and release between the intake valve side drive rocker arm (37) and the intake valve side free rocker arm (39) can be switched. and a connection switching unit (53 _2), the exhaust valve driving means (29 _E) is, the exhaust of the exhaust valve in conjunction with (V _E), and the exhaust valve-side driving rocker arms which are connected (45), the camshaft (28) An exhaust valve side free rocker arm (46) abutting on the valve operating cam (34), and a connection switching hand capable of switching connection and release between the exhaust valve side drive rocker arm (45) and the exhaust valve side free rocker arm (46). In those containing (55 ₂₎ and,
The intake valve side drive rocker arm (37) is provided with a first contact portion (37a) extending toward the camshaft (28) side in the direction along the axis of the camshaft (28), on the intake valve side free rocker arm (39) side. The first contact portion (37a) and the second contact portion (45a) provided on the exhaust valve side drive rocker arm (45) and extending toward the camshaft (28), while co-located in the direction along the axis of the camshaft (28), the two abutment (37a, 45a) of the intake valve (V _I) and exhaust valves (V _E) for closed pause In contact with a perfect circular rest portion (33 ₂ ) provided on the camshaft (28) ,
The common resting portion (33 ₂ ) is close to the intake valve side drive rocker arm (37) of the intake valve side operation cam (35) where the roller (43) pivotally supported by the intake valve side free rocker arm (39) is in rolling contact. A valve operating apparatus for an SOHC type internal combustion engine, wherein the valve operating apparatus is located on one side of the internal combustion engine.

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